Lubricant is preferably applied in an aqueous dispersion. To prevent coagulation of the solids in the aqueous dispersion on the one hand and to obtain a heat-resistant uniform lubricating film on the other hand, the high-temperature lubricant additionally contains, apart from a solid lubricant, an organic product which decomposes without residue, an inorganic additive of polyphosphate, a boron compound and an alkali metal silicate, and also an organic stabiliser.